I am connected but nothing appears on client

DCS World has been minimized: LotAtc routines are no more called, prefer running in windowed mode or let DCS World not minimized.

DCS World is in pause, no data are send during pause mode :)

There is no AWACS or ground radar in the mission, nothing can be see… (change detection profiles or add an AWACS or ground radar in the mission)

You run DCS + LotAtc client on same computer

If your DCS is in fullscreen mode, when you minimized it, all export are stopped and LotAtc cannot receive any update. I +cannot do something to fix that+. The solutions is to uncheck fullscreen option in DCS (window mode is not affected).